In addition, Apple's first and only keyboard dock used the iPad in portrait mode. I bought one on day-1 of the iPad 1. It was a terrific dock. It was very enjoyable to work on documents in portrait mode.
With all of the rumors floating around, it is a bit difficult to merge them all into a single device that makes sense. SOME of those rumors are not going to come to be reality.
I think it is possible for Apple to have redesigned the smart keyboard to be modeled after Google's Pixel (C and Slate) keyboards... utilizing magnets to allow multiple angles and even orientations... provided there were smart connectors for portrait and landscape modes.
Either way, it'll be interesting.